Transgenic MSH overexpression attenuates the metabolic effects of a high-fat diet

Michelle Lee, Andrea Kim, Streamson C. Chua, Silvana Obici, Sharon L. Wardlaw

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

To determine whether long-term melanocortinergic activation can attenuate the metabolic effects of a high fat diet, mice overexpressing an NH 2-terminal POMC transgene that includes α- and γ3-MSH were studied on either a 10% low-fat diet (LFD) or 45% high-fat diet (HFD). Weight gain was modestly reduced in transgenic (Tg-MSH) male and female mice vs. wild type (WT) on HFD (P < 0.05) but not LFD. Substantial reductions in body fat percentage were found in both male and female Tg-MSH mice on LFD (P < 0.05) and were more pronounced on HFD (P < 0.001). These changes occurred in the absence of significant feeding differences in most groups, consistent with effects of Tg-MSH on energy expenditure and partitioning. This is supported by indirect calorimetry studies demonstrating higher resting oxygen consumption and lower RQ in Tg-MSH mice on the HFD. Tg-MSH mice had lower fasting insulin levels and improved glucose tolerance on both diets. Histological and biochemical analyses revealed that hepatic fat accumulation was markedly reduced in Tg-MSH mice on the HFD. Tg-MSH also attenuated the increase in corticosterone induced by the HFD. Higher levels of Agrp mRNA, which might counteract effects of the transgene, were measured in Tg-MSH mice on LFD (P = 0.02) but not HFD. These data show that long-term melanocortin activation reduces body weight, adiposity, and hepatic fat accumulation and improves glucose metabolism, particularly in the setting of diet-induced obesity. Our results suggest that long-term melanocortinergic activation could serve as a potential strategy for the treatment of obesity and its deleterious metabolic consequences.

Original languageEnglish (US)
Pages (from-to)E121-E131
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume293
Issue number1
DOIs
StatePublished - Jul 1 2007

Keywords

  • Diabetes
  • Hepatic steatosis
  • Melanocortins
  • Melanocyte-stimulating hormone
  • Obesity
  • Proopiomelanocortin

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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